Scanning devices for analyzing liquid samples delivered thereto are well known, which devices employ electrical, optical, acoustical, or like means, for making desired measurements on the samples. Some such devices are best adapted for operation on a single sample of relatively large volume. After feeding the sample through the device, operation is stopped and the sample delivery portion thereof is washed in preparation for another sample. This may require substantial time and often dismantling of the device. Other such scanning devices for handling large numbers of samples are fully automated, requiring substantially no operator attention or assistance. Such devices are complicated and expensive. The present invention is directed to an inexpensive, semi-automatic, sample delivery system for scanning devices whereby a relatively large number of small samples may be fed to the scanning device under operator control with minimum inconvenience over a short time period.